A study published in the March issue of Biological Psychology suggests that the shorter a man's index finger is compared with his ring finger, the more physically aggressive he is likely to be.
It has been known for more than 100 years that men, unlike women, usually have ring fingers longer than their index fingers.

Using a questionnaire designed to test aggressive tendencies, the researchers examined 298 men and women, all of them psychology students, and then measured their fingers. Researchers discovered that in men there is a significant statistical correlation between a low index finger length RATIO, to the ring finger and a propensity for physically aggressive behavior.

Finger length ratio in men did not correlate with measures of anger, hostility or verbal aggression But it did correlated significantly with a tendency toward physical aggression.

No one is quite sure why, but scientists believe that finger length ratio and the propensity for aggression are both influenced by the level of prenatal testosterone exposure during development.
Female finger length ratios showed no correlation with any of the measures.

"Can't help beating up the wife Judge. My index finger is very short and my ring finger is very long, kapisch?"

"You will never find a real Human being - Even in a mirror." ....Mike Kremer.